Android phone users can no longer buy e-books on the Kindle app from the Amazon website because of a change in policy by the Google Play store.
From June 1 Amazon stopped Android users making purchases on the official Kindle app, with billing options not only removed from the Amazon Kindle app but also from the Music and Audible apps. It comes in response to changes made on Google Play Store's billing policy. In May Amazon also removed the ability to buy digital goods from the its Shopping and Prime Video apps.
In a message addressing Kindle users, Amazon said: "Readers will no longer be able to buy or rent Kindle books or subscribe to Kindle Unlimited through the Amazon app for Android: this change keeps the app in compliance with Google's updated Play Store policies. You can always add to your library by buying or renting books through amazon.com from a web browser."